using System;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.Security.Cryptography;

namespace Server
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Title = "Server";
            TcpListener listener = new TcpListener(IPAddress.Parse("46.20.46.198"), 81);
            listener.Start();

            Console.WriteLine("Listening on {0}", listener.LocalEndpoint);

            while (true)
            {
                try
                {
                    Socket s = listener.AcceptSocket();

                    byte[] bytesToReveive = new byte[2048];
                    int received = s.Receive(bytesToReveive, 0, bytesToReveive.Length, SocketFlags.None);

                    Array.Resize(ref bytesToReveive, received);

                    string data = Decrypt(Encoding.Default.GetString(bytesToReveive), true);

                    string[] dataArray = data.Split('/');

                    string username = dataArray[0];
                    string password = dataArray[1];

                    byte[] bytesToSend = new byte[2048];

                    if (UserManagment.Exists(username, password))
                    {
                        string login = UserManagment.Autentication(username);

                        switch (login)
                        {
                            case "-1":
                                Console.ForegroundColor = ConsoleColor.DarkYellow;
                                Console.WriteLine(s.RemoteEndPoint + " | " + DateTime.Now);
                                Console.WriteLine("Username: {0}", username);
                                Console.WriteLine("Warning: Username has been banned.\n");
                                break;
                            case "2":
                                Console.ForegroundColor = ConsoleColor.DarkYellow;
                                Console.WriteLine(s.RemoteEndPoint + " | " + DateTime.Now);
                                Console.WriteLine("Username: {0}", username);
                                Console.WriteLine("Warning: Not allowed to login.\n");
                                break;
                            default:
                                Console.ForegroundColor = ConsoleColor.DarkGreen;
                                Console.WriteLine(s.RemoteEndPoint + " | " + DateTime.Now);
                                Console.WriteLine("Username: {0}", username);
                                Console.WriteLine("Success: {0}\n", login);
                                break;
                        }

                        bytesToSend = Encoding.Default.GetBytes(Encrypt(login, true));
                        s.Send(bytesToSend, 0, bytesToSend.Length, SocketFlags.None);
                    }
                    else
                    {
                        bytesToSend = Encoding.Default.GetBytes(Encrypt("0", true));
                        s.Send(bytesToSend, 0, bytesToSend.Length, SocketFlags.None);
                        Console.ForegroundColor = ConsoleColor.DarkMagenta;
                        Console.WriteLine(s.RemoteEndPoint + " | " + DateTime.Now);
                        Console.WriteLine("Failed: Username/Password Incorrect.\n");
                    }
                }
                catch
                {
                    Console.ForegroundColor = ConsoleColor.DarkMagenta;
                    Console.WriteLine(DateTime.Now);
                    Console.WriteLine("Failed: Bad Request\n");
                }
            }
        }

        public static string Encrypt(string toEncrypt, bool useHashing)
        {
            byte[] keyArray;
            byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

            string key = "mpiuqgi6zO8uoVogsBp8h5v9g7EuQ3bSBlM9agqA2Nnm4elloOfENIUFGHdW";
            if (useHashing)
            {
                MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));

                hashmd5.Clear();
            }
            else
                keyArray = UTF8Encoding.UTF8.GetBytes(key);

            TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
            tdes.Key = keyArray;
            tdes.Mode = CipherMode.ECB;

            tdes.Padding = PaddingMode.PKCS7;

            ICryptoTransform cTransform = tdes.CreateEncryptor();
            byte[] resultArray =
              cTransform.TransformFinalBlock(toEncryptArray, 0,
              toEncryptArray.Length);
            tdes.Clear();
            return Convert.ToBase64String(resultArray, 0, resultArray.Length);
        }

        public static string Decrypt(string cipherString, bool useHashing)
        {
            byte[] keyArray;

            byte[] toEncryptArray = Convert.FromBase64String(cipherString);

            string key = "mpiuqgi6zO8uoVogsBp8h5v9g7EuQ3bSBlM9agqA2Nnm4elloOfENIUFGHdW";

            if (useHashing)
            {
                MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));

                hashmd5.Clear();
            }
            else
            {
                keyArray = UTF8Encoding.UTF8.GetBytes(key);
            }

            TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
            tdes.Key = keyArray;

            tdes.Mode = CipherMode.ECB;
            tdes.Padding = PaddingMode.PKCS7;

            ICryptoTransform cTransform = tdes.CreateDecryptor();
            byte[] resultArray = cTransform.TransformFinalBlock(
                                 toEncryptArray, 0, toEncryptArray.Length);

            tdes.Clear();
            return UTF8Encoding.UTF8.GetString(resultArray);
        }
    }
}